The present invention relates to electrical adapters. More particularly, the present invention pertains to electrical adapters for use with packaged devices, e.g., adapters for ball grid array packages.
Certain types of integrated circuit packages are becoming increasingly popular due to their occupancy area efficiency. In other words, they occupy less area on a target board on which they are mounted while providing a high density of contact terminals. For example, one such high density package type is a ball grid array package. Generally, ball grid array packages contain an integrated circuit having its die bond pads electrically connected to respective conductive solder spheres that are distributed on the bottom surface of the package in an array. A target printed circuit board typically has formed on its surface a corresponding array of conductive pads which are aligned with the array of solder spheres for electrically mounting the ball grid array package on the target board. The target board typically includes other conductive traces and elements which lead from the array of conductive pads used for mounting the ball grid array package to other circuitry on the board for connecting various components mounted thereon. Typically, to mount such a ball grid array package to a target board, the package is positioned with the array of solder spheres corresponding to the array of conductive pads on the target board. The resulting structure is then heated until the solder sphere is melted and fused to the conductive pads of the target board.
Such area efficient packaging, e.g., ball grid array packages, provide a high density of terminals at a very low cost. Also, this packaging provides for limited lead lengths. The limited lead lengths may reduce the risk of damage to such leads of the package, may provide for higher speed product, etc. Generally, circuit boards and/or components mounted thereon are tested by designers as the circuit boards are being developed. For a designer to test a circuit board which utilizes a ball grid array package, the designer must first electrically connect the solder balls on the ball grid array package to the target board. As described above, this generally includes mounting the ball grid array package on the target board and heating the solder spheres to fuse the solder spheres to the conductive pads of the target board. Therefore, the package may be prevented from being used again. It is desirable for various reasons to reuse ball grid array packages after testing. For example, such ball grid array packages may be relatively expensive. Further, the solder spheres when fused to the conductive pads of the target board are not accessible for testing purposes and also it is difficult to rework the target board with the package soldered thereon.
Various adapters for ball grid array packages which electrically connect a ball grid array package to a target printed circuit board without requiring that the solder balls on the ball grid array package be fused to the target board are known. For example, one such adapter is shown in U.S. Pat. No. 5,892,245 to Hilton, issued Apr. 6, 1999 and entitled xe2x80x9cBall Grid Array Package Emulator.xe2x80x9d However, the high density of terminals for certain packages, e.g., ball grid array packages, micro ball grid array packages, and chip scale packages, lead to various interconnect problems for adapters being used with such packages. For example, such a high density of terminals, e.g., solder spheres, of such packages may lead to isolation problems between conductive elements of conventional adapters used for connecting the package to the target board. For example, to provide an adapter which is generally of the same size (e.g., same length and width) as the integrated circuit package leaves little room for insulating material between conductive elements of the adaptor used to connect the solder spheres to the target board. Further, for example, accessing the internal electrical signal of the adapter is difficult, it may be difficult to connect a logic analyzer or other test equipment thereto, and it may be difficult to plug a daughter circuit board thereto for various analysis purposes.
The present invention provides a small adapter apparatus usable for high density integrated circuit packages, e.g., ball grid array packages, micro ball grid array packages, flip chip packages, and chip scale packages. An adapter apparatus according to the present invention includes an adapter body member having a length along an adapter axis between a first adapter end and a second adapter end of the adapter body member. An array of contact elements, e.g., solder spheres, are disposed on the first adapter end of the adapter body member. Further, the adapter apparatus includes an array of elongated pin elements. Each elongated pin element corresponds to one of the array of contact elements and extends parallel to the adapter axis from a corresponding contact element through the adapter body member and the second adapter end thereof. One or more of the elongated pin elements of the array is of a different length than one or more other elongated pin elements.
In one embodiment of the adapter apparatus, the array of elongated pin elements includes at least a first set of elongated pin elements of a first length and a second set of elongated pin elements of a second length. At least one of the elongated pin elements of the first set is positioned between two elongated elements of the second set.
In another embodiment of the adapter apparatus, the array of elongated pin elements includes rows and columns of elongated pin elements. The rows and columns of elongated pin elements are arranged along x and y axes perpendicular to the adapter axis. Further, each elongated pin element is of a different length than elongated pin elements adjacent thereto along the x and y axes.
In yet another embodiment of the adapter apparatus, the apparatus includes a socket device to receive the elongated pin elements. The socket device includes a socket body member having a length along a socket axis between a first body member end and a second body member end thereof. The socket device further includes an array of socket elements arranged in the socket body member generally parallel to the socket axis as a function of the array of elongated pin elements. Each socket element extends at least between the first body member end and the second body member end.
In various embodiments of the socket device, the socket device may be configured as a female-to-male socket device. In other embodiments of the socket device, the socket device may be configured as a female-to-female socket device.
Further, in one embodiment of the socket device, the array of socket elements include at least a first set of socket elements and a second set of socket elements. The first set of socket elements is provided in the socket body member to receive elongated pin elements of the array of elongated pin elements having a first length, and the second set of socket elements is provided in the socket body member to receive elongated pin elements of the array of elongated pin elements having a second length.
Further, in yet another embodiment of the socket device, each of the socket elements of the first set include conductive socket retaining portions to receive and retain the elongated pin elements having a first length and each of the socket elements of the second set include conductive socket retaining portions to receive the elongated pin elements having a second length. The conductive socket retaining portions of the first set are offset along the direction of the socket axis from conductive socket retaining portions of the second set.
In yet another embodiment of the adapter apparatus, the socket device includes a first socket body member portion having a length along a socket axis between a first body member end and a second body member end thereof Further, the socket device includes a second socket body member portion having a length along a socket axis between a first body member end and a second body member end thereof. A first array of socket elements are arranged in the first socket body member portion generally parallel to the socket axis thereof configured to receive elongated pin elements of a first length and a second array of socket elements are arranged in the second socket body member portion generally parallel to the socket axis thereof configured to receive elongated pin elements of a second length. A printed wiring board is positioned between the first and second socket body member portions of the socket device.
Another adapter apparatus according to the present invention includes a socket body member having a length along a socket axis between a first body member end and a second body member end thereof. The adapter apparatus further includes an array of socket elements arranged in the socket body member generally parallel to the socket axis configured to receive an array of elongated pin elements. The array of socket elements include at least a first set of socket elements and a second set of socket elements. Each of the socket elements of the first set include conductive socket retaining portions to receive and retain elongated pin elements having a first length and each of the socket elements of the second set include conductive socket retaining portions to receive and retain the elongated pin elements having a second length. The conductive socket retaining portions of the first set are offset along the direction of the socket axis from the conductive socket retaining portions of the second set.
In one embodiment of the adapter apparatus, the conductive socket retaining portions of the first and second set of the socket elements include socket pin elements extending therefrom. In other words, this provides a female-to-male socket device.
In yet another embodiment of the adapter apparatus, the conductive socket retaining portions of the first and second set of socket elements include back-to-back conductive socket retaining portions open in opposing directions along the socket axis. In other words, this provides a female-to-female socket device.
In various embodiments of the present invention, various portions of the socket elements are adjacent and insulated from other portions thereof. Such insulation provides for minimized cross-talk between conductive portions of the socket elements and pins received in such socket elements.
In yet another embodiment of the adapter apparatus, the array of socket elements include rows and columns of socket elements. The rows and columns of socket elements are arranged along x and y axes perpendicular to the socket axis. Each conductive socket retaining portion is offset along the direction of the socket axis from conductive socket retaining portions adjacent thereto along the x and y axes.